Mental deficiency does not make a culture or society. It's not sufficient to say they are a "group". It has to be a national, racial, religious, or ethnic group.
Famously, those with other ailments such as deafness or blindness have gone on to form their own subcultures. This of course never happened with the likes of Downs because they are not a "group" broadly and autonomously forming a culture. They are dependent on care, usually, and at the very least for a good portion of their lives.
You seem to think the risks of carrying a child knowing they will have Downs are irrelevant and ought to be borne by the parent. That's irresponsible and naive.
Famously, those with other ailments such as deafness or blindness have gone on to form their own subcultures. This of course never happened with the likes of Downs because they are not a "group" broadly and autonomously forming a culture. They are dependent on care, usually, and at the very least for a good portion of their lives.
You seem to think the risks of carrying a child knowing they will have Downs are irrelevant and ought to be borne by the parent. That's irresponsible and naive.